This invention relates to the preparation of substantially pure p-phenoxybenzoyl compounds.
U.S. Pat. No. 3,953,400 to K. J. Dahl, Apr. 27, 1976, teaches the preparation of poly(arylene ether ketones) by polymerizing a p-phenoxybenzoyl moiety-containing monomer in the presence of a hydrogen fluoride-boron trifluoride catalyst and a capping agent. The monomer can be, for example, a p-phenoxybenzoyl halide, p-phenoxybenzoic acid or C.sub.1 -C.sub.3 alkyl p-phenoxybenzoates. The polymer produced by the process described in U.S. Pat. No. 3,953,400 contains the p-phenoxybenzoyl repeating unit having the structure ##STR1## The polymer has a tensile elongation to break of at least about 50% at room temperature and a main inherent viscosity within the range from about 0.8 to about 1.65. It has been found that in order to obtain satisfactory polymer product using the process described in the Dahl patent, substantially pure p-phenoxybenzoyl monomer must be used. The presence of even small amounts of impurities interferes with the polymerization process.